The goal of this mentored clinical scientist award is to promote the developing research skills of Carlos Blanco, M.D., Ph.D. a board- certified psychiatrist, by focusing in on the evaluation and treatment of methadone-maintained patients with comorbid pathological gambling. As a resident and fellow, Dr. Blanco has studied the course of substance abuse disorders with comorbid psychiatric disorders, and conducted preliminary studies on the biological basis and pharmacological treatment of pathological gambling. Over the course of this award, Dr. Blanco plans to carry out a program of research including cross-sectional studies of clinical severity and neuropsychological functioning in opiate dependent patients with and without pathological gambling and controls, and a randomized clinical trial of fluvoxamine combined with manual- guided cognitive-behavioral relapse-prevention therapy (CBT/RP) in methadone maintained patients with pathological gambling. This proposed research will be complemented by a training plan, under the sponsorship and guidance of Dr. Edward Nunes, together with the faculty and resources available at Columbia University. Dr. Blanco's training plan combines formal course work with individual tutorials with a range of expert consultants. He will receive training in the following areas: design and methods of clinical studies; controlled medication trials; methods of behavioral therapy research; neuropsychology; biostatistics and epidemiology. Together with the planned research, this program will provide Dr. Blanco with a unique training that will prepare him to conduct independent clinical research in the field of addictions and to achieve his long-term research career goal of increasing our understanding and improving the treatment of patients with substance abuse with comorbid pathological gambling.